From 4f97558e100f66f953ba7576b0ced146e6846997 Mon Sep 17 00:00:00 2001 From: zhanghailiang Date: Thu, 27 Oct 2016 14:42:57 +0800 Subject: COLO: Introduce checkpointing protocol We need communications protocol of user-defined to control the checkpointing process. The new checkpointing request is started by Primary VM, and the interactive process like below: Checkpoint synchronizing points: Primary Secondary initial work 'checkpoint-ready' <-------------------- @ 'checkpoint-request' @ --------------------> Suspend (Only in hybrid mode) 'checkpoint-reply' <-------------------- @ Suspend&Save state 'vmstate-send' @ --------------------> Send state Receive state 'vmstate-received' <-------------------- @ Release packets Load state 'vmstate-load' <-------------------- @ Resume Resume (Only in hybrid mode) Start Comparing (Only in hybrid mode) NOTE: 1) '@' who sends the message 2) Every sync-point is synchronized by two sides with only one handshake(single direction) for low-latency. If more strict synchronization is required, a opposite direction sync-point should be added. 3) Since sync-points are single direction, the remote side may go forward a lot when this side just receives the sync-point. 4) For now, we only support 'periodic' checkpoint, for which the Secondary VM is not running, later we will support 'hybrid' mode. Signed-off-by: zhanghailiang Signed-off-by: Li Zhijian Signed-off-by: Gonglei Cc: Eric Blake Cc: Markus Armbruster Cc: Dr. David Alan Gilbert Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Amit Shah Signed-off-by: Amit Shah --- migration/colo.c | 201 ++++++++++++++++++++++++++++++++++++++++++++++++- migration/trace-events | 2 + qapi-schema.json | 25 ++++++ 3 files changed, 226 insertions(+), 2 deletions(-) diff --git a/migration/colo.c b/migration/colo.c index 3a0d8043e6..fcc9047595 100644 --- a/migration/colo.c +++ b/migration/colo.c @@ -15,6 +15,7 @@ #include "migration/colo.h" #include "trace.h" #include "qemu/error-report.h" +#include "qapi/error.h" bool colo_supported(void) { @@ -35,22 +36,147 @@ bool migration_incoming_in_colo_state(void) return mis && (mis->state == MIGRATION_STATUS_COLO); } +static void colo_send_message(QEMUFile *f, COLOMessage msg, + Error **errp) +{ + int ret; + + if (msg >= COLO_MESSAGE__MAX) { + error_setg(errp, "%s: Invalid message", __func__); + return; + } + qemu_put_be32(f, msg); + qemu_fflush(f); + + ret = qemu_file_get_error(f); + if (ret < 0) { + error_setg_errno(errp, -ret, "Can't send COLO message"); + } + trace_colo_send_message(COLOMessage_lookup[msg]); +} + +static COLOMessage colo_receive_message(QEMUFile *f, Error **errp) +{ + COLOMessage msg; + int ret; + + msg = qemu_get_be32(f); + ret = qemu_file_get_error(f); + if (ret < 0) { + error_setg_errno(errp, -ret, "Can't receive COLO message"); + return msg; + } + if (msg >= COLO_MESSAGE__MAX) { + error_setg(errp, "%s: Invalid message", __func__); + return msg; + } + trace_colo_receive_message(COLOMessage_lookup[msg]); + return msg; +} + +static void colo_receive_check_message(QEMUFile *f, COLOMessage expect_msg, + Error **errp) +{ + COLOMessage msg; + Error *local_err = NULL; + + msg = colo_receive_message(f, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; + } + if (msg != expect_msg) { + error_setg(errp, "Unexpected COLO message %d, expected %d", + msg, expect_msg); + } +} + +static int colo_do_checkpoint_transaction(MigrationState *s) +{ + Error *local_err = NULL; + + colo_send_message(s->to_dst_file, COLO_MESSAGE_CHECKPOINT_REQUEST, + &local_err); + if (local_err) { + goto out; + } + + colo_receive_check_message(s->rp_state.from_dst_file, + COLO_MESSAGE_CHECKPOINT_REPLY, &local_err); + if (local_err) { + goto out; + } + + /* TODO: suspend and save vm state to colo buffer */ + + colo_send_message(s->to_dst_file, COLO_MESSAGE_VMSTATE_SEND, &local_err); + if (local_err) { + goto out; + } + + /* TODO: send vmstate to Secondary */ + + colo_receive_check_message(s->rp_state.from_dst_file, + COLO_MESSAGE_VMSTATE_RECEIVED, &local_err); + if (local_err) { + goto out; + } + + colo_receive_check_message(s->rp_state.from_dst_file, + COLO_MESSAGE_VMSTATE_LOADED, &local_err); + if (local_err) { + goto out; + } + + /* TODO: resume Primary */ + + return 0; +out: + if (local_err) { + error_report_err(local_err); + } + return -EINVAL; +} + static void colo_process_checkpoint(MigrationState *s) { + Error *local_err = NULL; + int ret; + s->rp_state.from_dst_file = qemu_file_get_return_path(s->to_dst_file); if (!s->rp_state.from_dst_file) { error_report("Open QEMUFile from_dst_file failed"); goto out; } + /* + * Wait for Secondary finish loading VM states and enter COLO + * restore. + */ + colo_receive_check_message(s->rp_state.from_dst_file, + COLO_MESSAGE_CHECKPOINT_READY, &local_err); + if (local_err) { + goto out; + } + qemu_mutex_lock_iothread(); vm_start(); qemu_mutex_unlock_iothread(); trace_colo_vm_state_change("stop", "run"); - /* TODO: COLO checkpoint savevm loop */ + while (s->state == MIGRATION_STATUS_COLO) { + ret = colo_do_checkpoint_transaction(s); + if (ret < 0) { + goto out; + } + } out: + /* Throw the unreported error message after exited from loop */ + if (local_err) { + error_report_err(local_err); + } + if (s->rp_state.from_dst_file) { qemu_fclose(s->rp_state.from_dst_file); } @@ -65,9 +191,33 @@ void migrate_start_colo_process(MigrationState *s) qemu_mutex_lock_iothread(); } +static void colo_wait_handle_message(QEMUFile *f, int *checkpoint_request, + Error **errp) +{ + COLOMessage msg; + Error *local_err = NULL; + + msg = colo_receive_message(f, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; + } + + switch (msg) { + case COLO_MESSAGE_CHECKPOINT_REQUEST: + *checkpoint_request = 1; + break; + default: + *checkpoint_request = 0; + error_setg(errp, "Got unknown COLO message: %d", msg); + break; + } +} + void *colo_process_incoming_thread(void *opaque) { MigrationIncomingState *mis = opaque; + Error *local_err = NULL; migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, MIGRATION_STATUS_COLO); @@ -85,9 +235,56 @@ void *colo_process_incoming_thread(void *opaque) */ qemu_file_set_blocking(mis->from_src_file, true); - /* TODO: COLO checkpoint restore loop */ + colo_send_message(mis->to_src_file, COLO_MESSAGE_CHECKPOINT_READY, + &local_err); + if (local_err) { + goto out; + } + + while (mis->state == MIGRATION_STATUS_COLO) { + int request; + + colo_wait_handle_message(mis->from_src_file, &request, &local_err); + if (local_err) { + goto out; + } + assert(request); + /* FIXME: This is unnecessary for periodic checkpoint mode */ + colo_send_message(mis->to_src_file, COLO_MESSAGE_CHECKPOINT_REPLY, + &local_err); + if (local_err) { + goto out; + } + + colo_receive_check_message(mis->from_src_file, + COLO_MESSAGE_VMSTATE_SEND, &local_err); + if (local_err) { + goto out; + } + + /* TODO: read migration data into colo buffer */ + + colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_RECEIVED, + &local_err); + if (local_err) { + goto out; + } + + /* TODO: load vm state */ + + colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_LOADED, + &local_err); + if (local_err) { + goto out; + } + } out: + /* Throw the unreported error message after exited from loop */ + if (local_err) { + error_report_err(local_err); + } + if (mis->to_src_file) { qemu_fclose(mis->to_src_file); } diff --git a/migration/trace-events b/migration/trace-events index a29e5a09ea..f374c8cf27 100644 --- a/migration/trace-events +++ b/migration/trace-events @@ -210,3 +210,5 @@ migration_tls_incoming_handshake_complete(void) "" # migration/colo.c colo_vm_state_change(const char *old, const char *new) "Change '%s' => '%s'" +colo_send_message(const char *msg) "Send '%s' message" +colo_receive_message(const char *msg) "Receive '%s' message" diff --git a/qapi-schema.json b/qapi-schema.json index 8b212152a3..cafada86e6 100644 --- a/qapi-schema.json +++ b/qapi-schema.json @@ -787,6 +787,31 @@ { 'command': 'migrate-start-postcopy' } ## +# @COLOMessage +# +# The message transmission between Primary side and Secondary side. +# +# @checkpoint-ready: Secondary VM (SVM) is ready for checkpointing +# +# @checkpoint-request: Primary VM (PVM) tells SVM to prepare for checkpointing +# +# @checkpoint-reply: SVM gets PVM's checkpoint request +# +# @vmstate-send: VM's state will be sent by PVM. +# +# @vmstate-size: The total size of VMstate. +# +# @vmstate-received: VM's state has been received by SVM. +# +# @vmstate-loaded: VM's state has been loaded by SVM. +# +# Since: 2.8 +## +{ 'enum': 'COLOMessage', + 'data': [ 'checkpoint-ready', 'checkpoint-request', 'checkpoint-reply', + 'vmstate-send', 'vmstate-size', 'vmstate-received', + 'vmstate-loaded' ] } + # @MouseInfo: # # Information about a mouse device. -- cgit v1.2.3